Layout design for disc cutters based on analysis of TBM cutter-head structure

Studies to date have failed to consider gage disc cutters' variable cutting depth and the constraints of cutter-head welds, and have ignored the coupling mechanism between the profile of the full-face rock tunnel-boring machine (TBM) cutter-head and the assembled radius layout of the disc cutters. To solve these problems, an adaptive design method for studying cutter layout was proposed. Taking the bearing stress of the outermost gage disc cutter as an index, the profile of the cutter-head was determined. Using a genetic algorithm and based on the principles of equal life and equal wear, the assembled radii of the cutters were optimally designed. Boundary conditions of non-interference between the cutters, manholes, muck buckets and welding lines were given when a star layout pattern was used on cutters. The cutter-head comprehensive evaluation model was established by adopting relative optimization improvement degree of evaluation indices to achieve dimensional consistency. Exemplifying the MB264-311-8030 mm tape TBM cutter-head, the calculations show that compared with the original layout scheme, among the 51 disc cutters, the largest gap of the cutters' assembled radiuses is only 25.8 mm, which is 0.64% of the cutter-head's radius and is negligible. The cutter-head's unbalanced radial force decreases by 62.41%, the overturning moment decreases by 33.22%, and the cutter group's centroid shift increases by only 18.48%. Each index is better than or approximately equal to the original cutter-head layout scheme, and the equivalent stress and deformation are both smaller; these results fully verify the feasibility and effectiveness of the method.